Acrylic resins are well known to have excellent weather resistance. By making use of this characteristic, they are used as a capstock for a material requiring weather resistance. For example, U.S. Pat. No. 4,198,520 discloses improvement of weather resistance of the surface of a molding made of a material inferior in weather resistance such as ABS resin, PVC resin or the like by using an acrylic resin as a capstock for the surface. U.S. Pat. No. 5,318,737 and WO00/08098 discloses preparation of an acrylic resin composition suited for use as a capstock excellent in weather resistance and impact resistance by adding a rubber component to an acrylic resin.
However, acrylic resins are fragile materials so that addition of a large amount of rubber thereto is necessary for attaining impact resistance enough for satisfying the market demand, which leads to a deterioration in processability and surface hardness. A capstock well balanced between impact resistance and processability does not exist at present.